Bonnie Lowenthal (born February 19, 1940) is an American politician who represented California's 70th State Assembly district.

Lowenthal unsuccessfully ran for Mayor of Long Beach in 2014, failing to get past the primary nominating election, earning 19% of the vote.

She has also served as a bilingual mental health consultant for the League of United Latin American Citizens (LULAC), HeadStart, and the Centro de la Raza, Prior to her service in the Assembly, Lowenthal was elected to represent the First Council District of the City of Long Beach, in 2001, and was selected to serve as Vice Mayor in 2006.

Lowenthal was previously married to California State Senator Alan Lowenthal—who was also one of her predecessors in her assembly seat.

Daniel is a judge on a Superior Court, and Josh is a member of the California State Assembly.